tweak the README about the check for uncompressed size
tweak the README about the check for uncompressed size

Signed-off-by: Adam Salter <f257d94038124c89b9e3063ebb3ccaafdcb43ccb@gmail.com>
masterweb121/sitemap_generator,zBMNForks/sitemap_generator,SalzmanGroup/sitemap_generator,Velid/sitemap_generator,PikachuEXE/sitemap_generator,kjvarga/sitemap_generator,edusegzy/sitemap_generator,PikachuEXE/sitemap_generator,adamsalter/sitemap_generator,bolshakov/sitemap_generator,HisanoTakayasu/sitemap_generator,edusegzy/sitemap_generator,SalzmanGroup/sitemap_generator,jumph4x/spree_sitemap_generator,bolshakov/sitemap_generator,masterweb121/sitemap_generator,zBMNForks/sitemap_generator,Velid/sitemap_generator,HisanoTakayasu/sitemap_generator